Chronological Age, Somatic Maturation and Anthropometric Measures: Association with Physical Performance of Young Male Judo Athletes

Sport for children and adolescents must consider growth and maturation to ensure suitable training and competition, and anthropometric variables could be used as bio-banding strategies in youth sport. This investigation aimed to analyze the association between chronological age, biologic maturation, and anthropometric characteristics to explain physical performance of young judo athletes. Sixty-seven judokas (11.0–14.7 years) were assessed for anthropometric and physical performance. Predicted adult stature was used as a somatic maturation indicator. A Pearson’s bivariate correlation was performed to define which anthropometric variables were associated with each physical test. A multiple linear hierarchical regression was conducted to verify the effects of age, maturity, and anthropometry on physical performance. The regression models were built with age, predicted adult stature, and the three most significantly correlated anthropometric variables for each physical test. Older judokas performed better in most of the physical tests. However, maturation attenuated the age effect in most variables and significantly affected upper body and handgrip strength. Anthropometric variables attenuated age and maturity and those associated with body composition significantly affected the performance in most tests, suggesting a potential as bio-banding strategies. Future studies should investigate the role of anthropometric variables on the maturity effect in young judokas.

The same growth pattern from puberty suggests that modern human diversity results from changes during pre-pubertal development

Patterns of human growth established for one population have rarely been tested in other populations. In a previous study, three growth curves from puberty were modelled for each sex in a longitudinal study of a Caucasian population based on stature, age at peak of growth and biological maturation. Each curve represents the canalisation of growth associated with the type of puberty. The high precision (± 3 cm) of individual adult stature predictions shows that growth kinetics are already set up at puberty and are canalised depending on biological maturity. Our aim is to assess whether this model can be extrapolated to other populations to test whether growth canalisation is a population-dependent phenomenon or if the model reflects a canalisation pattern specific to our species. The modelled curves predicted adult stature with the same high degree of precision in basketball players and the Baka pygmies. Therefore, (1) the relationship between growth kinetics and age at maturity is similar in all populations and (2) growth according to pubertal stages follows the same canalisation patterns in the populations despite the wide differences in their average adult statures. It suggests that morphological diversity in modern humans results from processes taking place in early development.

Outcomes in children treated with growth hormone for Prader-Willi syndrome: data from the ANSWER Program® and NordiNet® International Outcome Study

Background Growth hormone (GH) deficiency is common in patients with Prader-Willi syndrome (PWS) and leads to short adult stature. The current study assessed clinical outcomes based on real-world observational data in pediatric patients with PWS who were treated with GH. Methods Data from patients previously naïve to treatment with GH who began therapy with somatropin were collected from 2006 to 2016 in the observational American Norditropin® Studies: Web-Enabled Research (ANSWER) Program® and NordiNet® International Outcome Study. Variables affecting change from baseline in height standard deviation scores (HSDS; n = 129) and body mass index standard deviation scores (BMI SDS; n = 98) were determined. Results Patients included in both HSDS and BMI SDS analyses were treated with a mean GH dose of 0.03 mg/kg/d (SD, 0.01 mg/kg/d). Results from the HSDS analysis revealed that baseline age and years on treatment had a significant impact on the change in HSDS. In the BMI SDS analysis, longer GH treatment time led to a greater change in BMI SDS from baseline, and patients with a higher BMI at the start of treatment had a greater decrease in BMI over time. Conclusions GH is effective in the management of children with PWS. Earlier treatment resulted in a greater gain in height, and a longer treatment period resulted in better outcomes for both height and BMI. Trial registration This study was registered with ClinicalTrials.gov (NCT01009905) on November 9, 2009.

Prader–Willi-Like Phenotype Caused by an Atypical 15q11.2 Microdeletion

We report a 17-year-old boy who met most of the major Prader–Willi syndrome (PWS) diagnostic criteria, including infantile hypotonia and poor feeding followed by hyperphagia, early-onset morbid obesity, delayed development, and characteristic facial features. However, unlike many children with PWS, he had spontaneous onset of puberty and reached a tall adult stature without growth hormone replacement therapy. A phenotype-driven genetic analysis using exome sequencing identified a heterozygous microdeletion of 71 kb in size at chr15:25,296,613-25,367,633, genome build hg 19. This deletion does not affect the SNURF-SNRPN locus, but results in the loss of several of the PWS-associated non-coding RNA species, including the SNORD116 cluster. We compared with six previous reports of patients with PWS who carried small atypical deletions encompassing the snoRNA SNORD116 cluster. These patients share similar core symptoms of PWS while displaying some atypical features, suggesting that other genes in the region may make lesser phenotypic contributions. Altogether, these rare cases provide convincing evidence that loss of the paternal copy of the SNORD116 snoRNA is sufficient to cause most of the major clinical features of PWS.

Sample-Selection Biases and the Historical Growth Pattern of Children

ABSTRACTBodenhorn et al. (2017) have sparked considerable controversy by arguing that the fall in adult stature observed in military samples in the United States and Britain during industrialization was a figment of selection on unobservables in the samples. While subsequent papers have questioned the extent of the bias (Komlos and A’Hearn 2019; Zimran 2019), there is renewed concern about selection bias in historical anthropometric datasets. Therefore, this article extends Bodenhorn et al.’s discussion of selection bias on unobservables to sources of children’s growth, specifically focusing on biases that could distort the age pattern of growth. Understanding how the growth pattern of children has changed is important because these changes underpinned the secular increase in adult stature and are related to child stunting observed in developing countries today. However, there are significant sources of unobserved selection in historical datasets containing children’s and adolescents’ height and weight. This article highlights, among others, three common sources of bias: (1) positive selection of children into secondary school in the late nineteenth and early twentieth centuries; (2) distorted height by age profiles created by age thresholds for enlistment in the military; and (3) changing institutional ecology that determines to which institutions children are sent. Accounting for these biases adjusts the literature in two ways: evidence of a strong pubertal growth spurt in the nineteenth century is weaker than formerly acknowledged and some long-run analyses of changes in children’s growth are too biased to be informative, especially for Japan.

Human Growth and Stature

This chapter reviews the study of stature in the archaeological record with a focus on the Roman period. A critical review of current methods of estimating stature, including an evaluation of the differing techniques and their application to the Roman period follows. This chapter does not advocate the comparison of long bone lengths alone for the study of stature in the Roman world. It argues that such an approach overlooks the biocultural significance of overall body proportions (including trunk height); instead more effort should be made to establish population-specific regression formulae. Finally, the chapter argues that because adult stature and final body proportions are strongly influenced by environmental conditions during childhood, a more nuanced consideration of growth and adversity during infancy and childhood is required.

Effects of Bio-Banding upon Physical and Technical Performance during Soccer Competition: A Preliminary Analysis

Bio-banded competition has been introduced to address the variation in physical maturity within soccer. To date, no research has investigated the effect of bio-banded competition relative to chronological competition. The current study investigated the effect of bio-banding upon physical and technical performance in elite youth soccer athletes. Twenty-five male soccer athletes (11–15 years) from an English Premier League soccer academy participated in bio-banded and chronological competition, with physical and technical performance data collected for each athlete. Athletes were between 85–90% of predicted adult stature, and sub-divided into early, on-time and late developers. For early developers, significantly more short passes, significantly less dribbles and a higher rating of perceived exertion (RPE) were evident during bio-banded competition compared to chronological competition (p < 0.05). Significantly more short passes and dribbles, and significantly fewer long passes were seen for on-time developers during bio-banded competition (p < 0.05). For late developers, significantly more tackles, and significantly fewer long passes were evident during bio-banded competition (p < 0.05). No significant differences in physical performance were identified between competition formats. Results demonstrated that bio-banded competition changed the technical demand placed upon athletes compared to chronological competition, without reducing the physical demands. Bio-banded competition can be prescribed to athletes of differing maturation groups dependent upon their specific developmental needs.